Implement Into<Infallible> when spi::DeviceError is infallible #718
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This improves integration with infallible SPI device driver APIs that constrain the SPI device error type to Into<Infallible>, allowing types such as DeviceError<Infallible, Infallible> to be used.
Dirbaio
approved these changes
Dec 2, 2025
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I'm currently writing a SPI device driver which can use any struct that implements
embedded_hal::spi::SpiDeviceinternally, such as aembedded_hal_bus::spi::ExclusiveDevice. I would like to provide an infallible API for platforms which have infallible SPI transactions, such as the RP2350. A SPI transaction on these platforms returnsResult<(), DeviceError<Infallible, Infallible>>if we use anExclusiveDevice, which can obviously be safely unwrapped.To write this API I create a simple wrapper struct around the original fallible API. I tried to constrain the error type by
Into<Infallible>such that any error type that is convertible toInfalliblecan be used. However,DeviceError<Infallible, Infallible>does not implement this trait yet. So I implemented it in this PR.Happy to hear opinions and possible alternatives, this was the first solution I saw.